In the prior art, a foldable dining chair for children includes a frame body which can be controlled in an open state and a folded state, and a seat mechanism disposed thereon. The described frame body is folded in back-and-forth direction and up-and-down direction thereof when it is in the folded state. The current foldable dining chairs for children commonly can be classified into two kinds that one has a simple structure while a larger size after being folded; and the other has a smaller size in its folded state, but has a more complex structure making folding process complicated.